Benadryl Allergy Sinus Headache Side Effects
Generic Name: acetaminophen / pseudoephedrine
Note: This page contains information about the side effects of acetaminophen / pseudoephedrine. Some of the dosage forms included on this document may not apply to the brand name Benadryl Allergy Sinus Headache.
Not all side effects for Benadryl Allergy Sinus Headache may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.
For the Consumer
Applies to acetaminophen / pseudoephedrine: capsules, tablets
Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Seek medical attention right away if any of these SEVERE side effects occur while taking acetaminophen / pseudoephedrine:
Constipation; diarrhea; dizziness; drowsiness; excitability; headache; loss of appetite; nausea; nervousness or anxiety; trouble sleeping; upset stomach; vomiting; weakness.
Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); difficulty urinating or inability to urinate; fast or irregular heartbeat; hallucinations; mood or mental changes; seizures; severe dizziness, lightheadedness, or headache; severe drowsiness; stomach pain; tremor; vision changes; yellowing of skin or eyes.
For Healthcare Professionals
Applies to acetaminophen / pseudoephedrine: oral capsule, oral liquid, oral tablet, oral tablet chewable
Cardiovascular adverse effects of pseudoephedrine have included significant rises in heart rate. Hypertension and arrhythmias have been problematic in susceptible patients.[Ref]
Pseudoephedrine causes vasoconstriction which generally does not produce hypertension, but may be problematic for patients with preexisting hypertension. Arrhythmias may be produced in predisposed patients. Rarely, pseudoephedrine has been reported to cause coronary artery spasm and chest pain.[Ref]
Nervous system side effects of pseudoephedrine have included nervous system stimulation, resulting in tremor, anxiety, and nervousness. Insomnia has been reported in up to 30% of pseudoephedrine-treated patients. Headache has also occurred in patients receiving pseudoephedrine.[Ref]
Hepatic side effects of acetaminophen have been rare, except in alcoholics and after overdose. In these settings, severe and sometimes fatal (3% to 4%) dose-dependent hepatitis has been reported. Several cases of hepatotoxicity from chronic acetaminophen therapy at therapeutic doses have also been reported despite a lack of risk factors for toxicity[Ref]
Alcoholic patients may develop hepatotoxicity after even modest doses of acetaminophen. In healthy patients, approximately 15 grams of acetaminophen is necessary to deplete liver glutathione stores by 70% in a 70 kg person, although hepatotoxicity has been reported with smaller doses. Glutathione concentrations may be repleted by the antidote N-acetylcysteine. One case report has suggested that hypothermia may also be beneficial in decreasing liver damage during overdose.
In a recent retrospective study of 306 patients admitted for acetaminophen overdose, 6.9% had severe liver injury but all recovered. None of the 306 patients died.
A 19-year-old female developed hepatotoxicity, reactive plasmacytosis and agranulocytosis followed by a leukemoid reaction after acute acetaminophen toxicity.[Ref]
One study has suggested that acetaminophen may precipitate acute biliary pain and cholestasis. The mechanism for this side effect may be related to inhibition of prostaglandin and alterations in the regulation of the sphincter of oddi.[Ref]
Gastrointestinal side effects of acetaminophen are rare, except in alcoholics and after overdose. Cases of acute pancreatitis have been reported rarely with acetaminophen use.
Gastrointestinal side effects of pseudoephedrine have included anorexia and gastric irritation in approximately 5% of patients. Dry mouth, nose, or throat has occurred in up to 15% of patients.[Ref]
Renal side effects of acetaminophen have been rare and included acute tubular necrosis and interstitial nephritis. Adverse renal effects were most often observed after overdose, after chronic abuse (often with multiple analgesics), or in association with acetaminophen-related hepatotoxicity.[Ref]
Acute tubular necrosis usually occurs in conjunction with liver failure, but has been observed as an isolated finding in rare cases.[Ref]
Hematologic side effects have included rare cases of thrombocytopenia associated with acetaminophen. Acute thrombocytopenia has also been reported as having been caused by sensitivity to acetaminophen glucuronide, the major metabolite of acetaminophen. Methemoglobinemia with resulting cyanosis has also been observed in the setting of acute overdose.[Ref]
Hypersensitivity reactions to pseudoephedrine have included fixed drug eruptions.[Ref]
Dermatologic side effects have included rare reports of general erythematous skin rashes associated with acetaminophen. A rare case of bullous erythema associated with acetaminophen has been reported. Acetaminophen has been associated with a risk of rare but potentially fatal serious skin reactions known as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP).[Ref]
Metabolic side effects including metabolic acidosis have been reported following a massive overdose of acetaminophen.
In the case of metabolic acidosis, causality is uncertain as more than one drug was ingested. The case of metabolic acidosis followed the ingestion of 75 grams of acetaminophen, 1.95 grams of aspirin, and a small amount of a liquid household cleaner. The patient also had a history of seizures which the authors reported may have contributed to an increased lactate level indicative of metabolic acidosis.
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